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Quick Answers
Short, worked answers to the material questions we hear most. Every number comes from the matching calculator, and each page links back to it so you can plug in your own sizes.
Concrete, Masonry & Paving
| How much concrete do I need for a 10x10 slab? | A 10x10 slab poured 4 inches thick takes 1.36 cubic yards of concrete, including 10% extra for waste. |
| How many 80 lb bags of concrete for a 10x10 slab 4 inches thick? | A 10x10 slab 4 inches thick needs 56 bags of 80 lb concrete before any waste allowance (75 bags if you buy 60 lb). |
| How much concrete do I need for a 12x12 patio? | A 12x12 patio at 4 inches thick needs 1.96 cubic yards of concrete with 10% waste, or 89 bags of 80 lb mix. |
| How much concrete for a 20x20 garage slab 6 inches thick? | A 20x20 garage slab poured 6 inches thick needs 8.15 cubic yards of concrete, including 10% for waste. |
| How many yards of concrete for a 24x24 garage? | A 24x24 garage floor at 5 inches thick takes 9.78 cubic yards of concrete with 10% waste added. |
| How many bricks do I need for a 10 ft long, 4 ft high wall? | A 10x4 ft single-wythe wall of modular bricks needs 288 bricks with 5% waste, plus about 9 bags of 70 lb Type N mortar. |
| How many pavers do I need for a 12x12 patio? | A 12x12 patio takes 713 standard 4x8 pavers with 10% waste, on 1.78 cubic yards of gravel base and 0.44 cubic yards of sand. |
| How much asphalt do I need for a 20x40 driveway? | A 20x40 driveway paved 3 inches thick (compacted) takes about 14.5 tons of hot mix asphalt. |
| How much sand do I need for a 12x12 paver patio? | A 12x12 paver patio needs 0.6 tons of bedding sand at 1 inch deep, which is 0.44 cubic yards or 24 bags of 50 lb. |
Landscaping & Outdoor
| How much gravel do I need for a 12x24 driveway? | A 12x24 driveway with 4 inches of crushed stone needs 3.56 cubic yards, which weighs about 4.98 tons. |
| How many bags of mulch do I need for 100 square feet? | Covering 100 square feet with 3 inches of mulch takes 13 bags of 2 cubic feet or 9 bags of 3 cubic feet (0.93 cubic yards). |
| How much mulch do I need for a 5x20 flower bed? | A 5x20 flower bed topped with 2 inches of mulch needs 0.62 cubic yards: 9 bags of 2 cubic feet or 6 bags of 3 cubic feet. |
| How much soil do I need for a 4x8 raised bed? | A 4x8 raised bed filled 12 inches deep holds 1.19 cubic yards of soil, or 32 one-cubic-foot bags. |
| How many pickets do I need for 100 feet of fence? | 100 feet of privacy fence with 5.5-inch pickets set tight together takes 219 pickets, plus 14 posts and 26 rails. |
| How much grass seed do I need for 1,000 square feet? | Seeding a new 1,000 sq ft lawn with tall fescue takes about 7 lb of seed. |
| How many deck boards do I need for a 12x16 deck? | A 12x16 deck with boards running the 16 ft direction needs 26 deck boards of 16 ft, on 13 joists at 16 inches on center. |
Interior
| How much paint do I need for a 12x12 room? | A 12x12 room with 8 ft walls, one door and two windows needs about 1.9 gallons for two coats, so buy 2 gallons. |
| How much paint for a 10x10 bedroom, including the ceiling? | A 10x10 bedroom with 8 ft walls, one door, one window and the ceiling needs about 2.2 gallons for two coats, so plan on 3 gallons. |
| How many tiles do I need for a 5x8 bathroom floor? | A 5x8 bathroom floor needs 44 tiles of 12x12 with 1/8 inch grout lines and 10% waste, which is 5 boxes of 10. |
| How many boxes of flooring for a 12x12 room? | A 12x12 room needs 8 boxes of flooring at 20 square feet per box, covering 158.4 square feet with 10% waste. |
| How many sheets of drywall for a 12x12 room? | A 12x12 room with 8 ft walls and a drywalled ceiling needs 19 sheets of 4x8 drywall with 10% waste. |
| How many rolls of wallpaper for a 12x12 room? | A 12x12 room with 8 ft walls, one door and two windows needs 9 standard rolls of wallpaper (20.5 in by 33 ft) with no pattern repeat. |
Roofing & HVAC
| How many bundles of shingles for a 1,500 sq ft house? | A 1,500 sq ft house (50x30 footprint with overhang) with a 4/12 roof needs 53 bundles of shingles, which is 17.4 squares. |
| What size air conditioner do I need for a 300 sq ft room? | A 300 sq ft room with average sun and two people needs about 6,000 BTU of cooling, which is half a ton. |
| What size AC unit do I need for 500 square feet? | A 500 sq ft space with average sun and two occupants needs about 10,000 BTU of cooling, or roughly 0.83 ton. |